Fig. 5

Seropositivity and level of antibody in seropositive individuals by exposure factors. Bar graphs show the percentage of seropositive and seronegative individuals within each exposure category. Comparison between groups, Chi square for trend/ Fisher’s exact test. Dot plots show the level of neutralizing antibody in seropositive individuals as percentage inhibition within each exposure category. Seropositivity designated at > 30% (manufacturers standard). A Face to face contact for > 15 min without mask with known RTP-PCR positive individual. B Workspace exposure: working in the same environment/ space as known RT-PCR positive individual. C Eating or socializing together with known RT-PCR positive individual with no protective measures. D Traveling together in company provided transport with known RT-PCR positive individual. Comparison between groups, Mann–Whitney test. *p < 0.05, **p < 0.01, ***p < 0.001